Description: (Taken directly from the application) The In-Patient Core is made up of two divisions, one at St. Luke?s-Roosevelt Hospital Center and the other at the New York-Presbyterian Hospital. Both the divisions are part of the Columbia University General Clinical Research Center. The In-Patient Core is an integral part of the NYORC, but funds for its operation are derived from a grant from NIH to Columbia University (Grant #M01 RR00645). The In-Patient Core is made available to qualified clinical investigators who wish to study questions related to human obesity which require hospitalization.